Only show a beforeunload dialog if a frame has had a user gesture since its load.

android_webview/javatests/src/org/chromium/android_webview/test/WebViewModalDialogOverrideTest.java

Index: android_webview/javatests/src/org/chromium/android_webview/test/WebViewModalDialogOverrideTest.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/WebViewModalDialogOverrideTest.java b/android_webview/javatests/src/org/chromium/android_webview/test/WebViewModalDialogOverrideTest.java
index c65fa0404ac37c8075e912b83833bc38663d98cf..1b6f76e707a629a7698accdf45bed320dc3dab2b 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/WebViewModalDialogOverrideTest.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/WebViewModalDialogOverrideTest.java
@@ -14,6 +14,7 @@ import android.support.test.filters.SmallTest;
 import org.chromium.android_webview.AwContents;
 import org.chromium.android_webview.JsPromptResultReceiver;
 import org.chromium.android_webview.JsResultReceiver;
+import org.chromium.android_webview.test.util.AwTestTouchUtils;
 import org.chromium.base.test.util.CallbackHelper;
 import org.chromium.base.test.util.Feature;
 
@@ -176,6 +177,8 @@ public class WebViewModalDialogOverrideTest extends AwTestBase {
         loadDataSync(awContents, client.getOnPageFinishedHelper(), BEFORE_UNLOAD_URL,
                 "text/html", false);
         enableJavaScriptOnUiThread(awContents);
+        // JavaScript onbeforeunload dialogs require a user gesture.
+        AwTestTouchUtils.simulateTouchCenterOfView(view);
 
         // Don't wait synchronously because we don't leave the page.
         int currentCallCount = jsBeforeUnloadHelper.getCallCount();